Collateral Ligament Injury
What is the collateral ligament?
All joints in the fingers and thumb have a collateral ligament on each side to keep the joint stable and stop the joint angling to either side. The "radial" collateral ligament (RCL) is on the side of the radius (the larger bone of the forearm) side and the "ulnar" collateral ligament (UCL) is on the ulnar (smaller bone of the forearm) side. These ligaments may be injured by a force in the direction that stretches the ligament and pulls it off bone. (image below left).
The most common collateral ligament injuries occur in the thumb. Collateral ligament injuries to the smaller joints rarely require surgical repair but it will take 3-4 months for the swelling and stiffness to resolve. Hand therapy to regain movement and protecting the injured ligament by buddy-taping are the mainstays of treatment.
What causes of collateral ligament injuries?
Most often these are a single traumatic injury. forcing the finger or thumb in an ulnar or radial direction. The classic injury to the thumb, "skier's thumb", occurs when the person falls with the pole in their hand, stretching then rupturing the UCL (image above right). The thumb RCL injury occurs when falling onto the thumb and stretching the RCL until it tears from bone.
Stener lesion - UCL thumb
A Stener lesion may occur when the thumb UCL is injured. This is where the ligament ruptures and the detached end flips over the top of the abductor aponeurosis (part of the tendon structure that attaches to the extensor tendon). This is a grade 3 injury and, because the ligament is separated from its site of attachment by the abductor aponeurosis, it will be unable to heal and restore stability. (See images).
How the Stener lesion occurs
Thumb UCL Stener lesion
What are the signs & symptoms?
The main symptoms are pain and joint swelling. The severity of symptoms will depend on the degree of ligament injury. In many cases, the degree of ligament injury can be assessed on examination.
Grade 1 - no laxity.
Grade 2 - mild laxity but a clear endpoint.
Grade 3 - marked laxity and no endpoint (Image left).
When the thumb ulnar collateral ligament is injured, pinch will be weak and painful, particularly in high grade injuries.
Diagnosis
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Examination is sufficient to diagnose many collateral ligament injuries. However, if presentation is delayed, stiffness of the join may mask the severity of the iigament injury.
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Ultrasound may be helpful indetermining the degree of ligament injury, particularly for thumb ulnar collateral ligament injuries.
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X-ray should always be performed to exclude a fracture. In younger patients, the bone where the ligament is attached may fracture and pull away instead of the ligament tearing off bone. (Image right)
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MRI may be required if the degree of ligament injury is unclear on examination or ultrasound.
X-ray showing avulsion fracture of the UCL bone attachment.
Non-Operative Treatment
Collateral ligament injuries WITHOUT or with MILD (Grade 1 or 2) laxity/instability on examination may be treated non-operatively. This involves a splint or short waterproof cast (thumb injuries) or buddy taping for most finger injuries. These measures protect the ligament from further injury while it heals. It generally takes 3 months before the ligament is able to take maximum stress without splint protection. Lifting heavy weights, contact sports and manual labour may be possible at 2-4 weeks WITH SPLINT PROTECTION). The specialist and hand therapist will guide your recovery.
The thumb UCL is used with all gripping and pinching activities splinting. Failure to protect the ligament while it heals may lead to further ligament injury and the need for surgery.
Surgical Treatment
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Complete collateral ligament tears with instability require repair.
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This is a day surgery performed under general anaesthetic.
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A small incision is made and the ligament repaired with a suture anchor.
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Dissolving stitches are used and long-acting anaesthetic keeps the area painfree for 6-8 hours.
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A protective fibreglass splint is applied and a sling and prescription for pain-relief provided.
Ligament Reconstruction
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Ligament injuries more than 6 weeks old may require reconstruction with a tendon graft.
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After 6 weeks, the ruptured ligament may retract with scar so it is not long enough to repair.
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The palmaris tendon is usually used. This tendon is present in 85% of the population and taking this tendon has no effect on function of the hand or wrist.
Risks of Surgery
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Nerve injury - 1% risk of a permanent numb patch on the back of the thumb.
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Joint stiffness - there will be a small degree of stiffness following the injury. To minimize stiffness, follow the exercise program, use regular panadol osteo and a heatpack before exercises.
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Re-rupture is very unlikely if the splinting and activity instructions are followed.
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Arthritis can occur if the joint is left unstable for many months.
Recovery
2 Days: Pain relief may be required, and the hand should be kept elevated to chest height. Driving should be possible within a few days.
2 weeks: Dressings reduced and a small thermoplastic splint is applied. An exercise program is started.
6 weeks: Change to a flexible neoprene splint (thumb). Continue light daily activities.
3-4 months: Returned to normal activities including gym and weight lifting.